The conjunctival papillae of the chick embryo are under study to determine the roles played by the peridermal cells in the development of the underlying perilimbic sclera. Specifically, we seek to describe the timetable and regional distribution of changes in the size, shape and surface characteristics of the peridermal cells and to correlate these changes with the development of the conjunctival papillae and of the scleral ossicles which arise under the influence of the papillae.